During the development and manufacturing of a seat system for an automotive vehicle multiple design and performance requirements must be satisfied. These design and performance requirements may be separated into various categories, including esthetic features, creature comfort and convenience specifications, seat system vehicle collision performance parameters, NVH performance characteristics, as well as other categories known in the art.
All of the above stated categories are not mutually exclusive, but rather are interrelated such that adjustment of an element in one category can affect elements in other categories. For example, to reduce NVH characteristics of a seat system the stiffness of the seat system is generally increased. However, when stiffness of a seat system is increased, seat system performance during a rear collision event is generally worse. Thus, a balanced relationship exists between NVH and collision performance characteristics of a seat system.
As another example, when adjusting the mass of a seat system, natural frequency of the seat system changes affecting NVH performance of the seat system. Depending upon the vehicle and the type of suspension contained therein, a vehicle typically experiences a “wheel hop” frequency of approximately between 12–17 Hz. It is desirable for a seat system to have a natural frequency of at least 1.5 Hz different, than the vehicle, so that wheel hop is not magnified in the seat system, which causes the seat system to resonate. Therefore, another balanced relationship exists between the mass of a seat system and NVH performance.
Additionally, it is not only desirable for a seat system to have a natural frequency that is at least 1.5 Hz different from that of the vehicle suspension, but that the seat system natural frequency also be greater than that of the vehicle suspension. The desire to have a seat system with a greater natural frequency than the vehicle suspension is due to the potential magnification affect on natural frequencies of bodily organs, which are generally below 12 Hz.
A significant and extensive amount of development and testing time and costs are typically involved and spent in order to satisfy requirements associated with each of the above stated categories. Often seat system parameters are repeatedly adjusted and readjusted to satisfy these requirements and many times the modifications are performed after a seat system has been designed, assembled and tested. The modifications occur in response to undesirable NVH test results of a complete seat system.
It is therefore desirable to provide a system for minimizing NVH characteristics of a seat system and a method for improving efficiency in design and development of the seat system. It is also desirable for the system to be simple, lightweight, and inexpensive to implement and manufacture.